1. eBeckett: Using Extended Analogy to Teach Fundamental Computing Concepts Damian Gordon eLearning Research Group, School of Computing, Dublin Institute of Technology, Kevin St., Dublin 8 ABSTRACT Computing concepts can often be complex and confusing, therefore one way for lecturers to address this potential problem is to use analogies to help explain key ideas. One of the most important ideas that a computing student must understand is the basic architecture of a digital computer. Since the late 1960s the standard teaching approach used to explain computer architecture is the Little Man Computer (LMC) Paradigm. This research seeks to expand upon this standard explanation through the use of a relatively recently developed technique called Extended Analogy. Extended analogy seeks to combine regular analogy with exaggeration or dramatic emphasis. In this case the LMC paradigm is extended by use of Samuel Beckett's play "Krapp's Last Tape". This play bears a striking resemblance to the basic LMC analogy, but has the additional advantage of being a dramatic piece which can help sustain the students interest and motivation. To fully exploit this new extended analogy the students were presented with a range of exercises which served to model many of the tasks that a professional software developer will be required to undertake. Additionally, and equally as significantly this extended analogy serves to illustrate another key computing concept, the concept of indirection. Indirection is a vital tool, and it exists in many forms; such as of pointers, lookup tables, hashing, overlay networks, etc. The exercises that the students were required to undertake included creative tasks such as writing a poem, writing a dramatic scene, and drawing pictures. They were designed to take cognisance of learning styles and, in particular, a new model of learning styles developed by the author. The complete process was assessed qualitatively and received a mostly positive reaction. INTRODUCTION "Focus on things that the students know and build upon them" - Enda Dunican 2 Learning to program can initially be very difficult for students. Two barriers to learning this skill are, firstly, the abstract nature of programming, concepts such as variables, data types, arrays, etc. have no real world counterparts, and secondly, programming requires an exactness of specification that contrasts strongly with the flexible nature of the English language. One teaching approach that has existed for many hundreds of years is teaching by analogy. This approach allows students to develop new ideas and new understandings based on existing and familiar understandings. This means that complex technical material can be taught through the use of analogies which can be more interesting ands captivating. This approach is widespread in teaching programming, examples of it can be found in [1] and [2]. A recent approach to this same problem is teaching by Extended Analogy [3]. Extended analogy combines analogy with high drama to make the lesson more memorable. This approach can help the student to remember the concept being taught using exaggeration or dramatisation [4,5]. In this research the concept being taught is the basic architecture of a computer, essentially how a computer computes. The architecture is explained using a Samuel Beckett play "Krapp's Last Tape" to illustrate the key operations of the system. The students are given a number of exercises to reinforce the ideas being taught and are given a questionnaire to provide them with the opportunity for feedback. Exercise 1: Chronology of Krapp After asking the students to read the play, the first exercise that they were required to undertake was an analysis of the text to create an internal chronology of the play. This exercise was designed to foster logical thinking and an analytical approach to problem-solving. Exercise 2: Krapp in Brief The second exercise that the students undertook was to create a summary of the play. This required that they go back and re-read the play slowly, and distil the salient points of the play. This is a very significant skill for an I.T. professional to have, the ability to recognise the most important points in a specification. Exercise 3: Krapp's Lost Tapes The next exercise was a creative one; to either write an additional scene for the play, write a poem about the play, or draw a picture of Krapp. This exercise required that the students access their creative abilities. This creatively has to be tapped into every time a computer program is written, it is a fundamental skill of any programmer. Exercise 4: Krapp in Action The final exercise the students undertook was simply to reflect on the work that was done and to identify what effect, if any, it had on them. The students were given a questionnaire to help in this process, to help them become reflective practitioners. These exercises also map onto various stages of a software development lifecycle. The first exercise (the analytical one) is like the analysis of requirements of a system. The second exercise (the practical one) is like the design phase of a system. The third exercise (the creative one) is like the development phase of a system. And the final exercise (the reflective one) is like the implementation and maintenance phases of a system. DIGITAL KRAPP LITTLE MAN COMPUTER PARADIGM "The LMC Paradigm has stood the test of time as a conceptual model" - Yurick & Osborne 7 Most computer architectures conform to the so-called von Neuman Architecture. This means that they execute programs by accessing both instructions and data on the same storage device. The computer performs the following sequence of steps; 1.Fetch the next instruction from memory at the address in the program counter 2.Decode the instruction using the control unit 3.The control unit commands the rest of the computer to execute the instruction 4.Go to step 1 This is the Fetch-Decode-Execute (FDE) cycle. These computers are known as Stored- Program Computers since the separation of storage from the processing unit is implicit in this model. A conceptual device or thought experiment to teach this architecture was developed by Stuart Madnick of MIT in the 1960s and is called the Little Man Computer (LMC) Paradigm [6,7]. The LMC Paradigm consists of a room with a 'Little Man' who simulates the operations of a computer. The room has an array of locations that store information (and instructions), an input and output tray, and a calculator. The analogy between the LMC and real computers is not perfect, but this approach is a simple and powerful conceptual model which allows students easy entry level to the basics of computer architecture. REFERENCES 1 Kim, J., Kim, J. The Impacts of Examples on Analogical Reasoning: On Programming Education, Technical Report, 1998. 2 Dunican, E. Making the Analogy: Alternative Delivery Techniques for First Year Programming Courses, PPIG 2002. 3 Matocha, J., Camp, T., Hooper, R. Extended Analogy: An Alternative Lecture Method, SIGCSE 1998: 262-266. 4 Goette, T., COBOL on Broadway: An Innovative Approach to Teaching Programming Concepts, Comm. of the International Information Management Association, 3, (2), 129--133, 2003. 5 Ben-Ari, M. Recursion: from drama to program. Journal of Computer Science Education 11(3), 1997, 9-12. KRAPP’S LAST TAPE “Between the idea and the reality falls the Shadow" - T.S. Elliot "Krapp's Last Tape" by Samuel Beckett has been called both "very straight-forward and accessible" [8] and "Beckett's most perfect piece of writing for the theatre"[9]. It was written in 1958 for actor Patrick Magee whose sonorous voice had captured Beckett's imagination after hearing him read from "Molloy" and "From an Abandoned Work" on BBC radio. The play was written in English and was provisionally entitled "Magee's Monologue". It is considered by many one of the most important plays written in the twentieth century. 6 Yurcik, W., Vila J. Brumbaugh L., An Interactive Web-Based Simulation of a General Computer Architecture, Proceedings of IEEE International Conference on Engineering and Computer Education, (August 2000). 7 Yurcik, W. Osborne, H. A Crowd of Little Man Computers: Visual Computer Simulator Teaching Tools, Proceedings of the 33nd conference on Winter simulation, December 09-12, 2001, Arlington, Virginia. 8 Coots, S. (2001) Samuel Beckett: A Beginner's Guide, Hodder and Arnold. 9 Fletcher, J. (2000) Faber Critical Guides Samuel Beckett Faber & Faber Ltd. 10 Gordon, D. & Bull, G. The Nexus Explored: A Generalised Model of Learning Styles 15 th International Conference of Society of Information Technology & Teacher Education 2004, Atlanta, Georgia, USA RESULTS AND CONCLUSION ”...good practice for understanding specifications..." ”...a bit of a laugh and brought the class together..." ”...it made me think outside the box..." - Student feedback As expected the outcome varied greatly from student to student. Those who excelled at one exercise often did less well in other exercises. So, for example, the first exercise which required the creation of a chronology resulted in a detailed analysis by some and a very superficial analysis by others. Equally with the practical and creative exercises different students did better at each one. The final questionnaire provided the students with the opportunity to comment on how they felt the entire process went for them, and reactions were somewhat mixed. Students with prior experience of programming (and, therefore, a range of preconceived notions) were less willing to participate in the process, whereas those with no prior experience were more willing to immerse themselves in the process and thus achieved more significant gains. The final outcomes for the 2004 - 2005 K268/1 Software Development class are available at http://www.comp.dit.ie/dgordon/KLT Teaching by analogy is an approach which has been used for many hundreds of years and has proven to be enormously beneficial (when properly implemented) whereas teaching by extended analogy is a relatively recent development and bears a great deal more investigation. "Krapp's Last Tape" centres on the idea of a single individual in a single room, recording and accessing information (on his tapes) by indirect means through his ledger. This clearly maps onto the LMC paradigm. The Little Man becomes Krapp, the LMC room becomes Krapp's Den, and the stored information becomes Krapp's Tapes. The analogy of the LMC paradigm becomes the extended analogy of "Krapp's Last Tape" which will hopefully be more dramatic and memorable for the students. Therefore, in an effort to assist the students understanding of the basic architecture of a digital computer, the students were required to read the play and undertake exercises based on it. Another benefit to this approach is that it exposes the students to the extremely important concept of indirection. Because Krapp does not directly search through his boxes of tapes, but rather locates the address of the appropriate tapes using his ledger ("…box three, spool five…"). This same indirect approach to accessing information can be seen throughout computer systems, for example, in pointers, which store the address of a particular variable (but not its value). Other examples of indirection can be seen in hashing, look-up tables, and overlay networks. Additionally the students were required to read a text which was difficult to understand at first but persistence helps make it much clearer. This is an important skill to develop for an I.T. professional, since they are often required to develop software for an organisation whose system may be expressed in its own business- specific terminology. This can seem like a daunting task at first, but a little practice can be of great benefit. Thus, these exercises were an ideal opportunity to begin developing the necessary patience and thoroughness required. The exercises were designed to encourage students to employ a range of skills and to help scaffold and encourage a creative approach to computing. The design of the exercises were based on a four-quadrant learning styles model developed by the author [10]. The exercises were as follows; "The life of every man is a diary in which he means to write one story, and writes another; and his humblest hour is when he compares the volume as it is with what he vowed to make it” - J.M. Barrie The play concerns Krapp, a 69-year-old man who is seen throughout the play residing in a single room. He records his memories regularly, and although all the recordings are made by the same person, the effect of listening back on older tapes gives the illusion of distinct identities. Each recording is logged by Krapp in a ledger for easy later retrieval. His initial interactions with his recordings are quite jovial; both Krapp and his past voice laugh together. As the play continues things become darker with Krapp expressing distaste for his younger self. John Hurt as Krapp (© Channel4.com)